Question

Can light ever be at rest? i know we've slowed light to about 35mph but is it possible to reach a rest state? would it still be light at that point?

Answer 1

A photon always moves at the speed of light measured in vacuum. It cannot slow down because that would imply a (little) lose in energy, which is not possible for a photon. However, the altering "speed" of light in a medium can be explained by absorption and emission of photons by atoms, which take a certain time.

Answer 2

Yes, light has been halted when passing through a medium of warm rubidium vapor. In a vacuum however, light always travels at a constant speed.

Answer 3

speed of light is always constant but, the apparent velocity can be slowed in a dense medium. The speed between atoms though is constant.

Answer 4

Actually, I don't remember where, but physicists have actually stopped light completely, obviously in a controlled environment.